1. Field of the Invention
The present invention relates to the field of sports equipment, and more particularly to the field of devices for the delivery of tennis balls to facilitate the practice of the basic tennis strokes.
2. Prior Art
Various types of ball throwing machines are well known in the prior art. Examples of such machines include baseball throwing machines and tennis ball throwing machines, which have been used for batting practice and the practice of the basic tennis ground strokes, respectively.
The ball throwing machines and machines for throwing other objects known in the prior art have utilized various throwing mechanisms. By way of example, throwing arms and slides have been utilized for throwing balls, clay pigeons and the like. Also compressed air and spinning wheels for receiving a ball therebetween have been used for the pitching of balls. However, tennis ball throwing machines having the various functions and controls of the present invention and being relatively inexpensive to manufacture are not known in the prior art.
In the case of tennis ball throwing machines, various functions and characteristics are highly desired. The basic function, of course, is to throw a tennis ball for the return by a player, preferably over a net on a standard tennis court. Accordingly, it is desired to have the machine be portable for easy transport and removal from a court, and further that the machine not require permanent anchors of any kind. Also, since the skill of the people using a machine will vary considerably, and in fact, normal play will involve various speeds, spins, positions, etc. it is desirable to be able to vary both the basic speed of the throw and the spin placed on the ball e.g., preferably varying amounts of forward spin and back spin. Other features of an ideal machine would include some form of oscillation of the throws from side to side so as to provide practice shots, both to the user's forehand and backhand, if desired, most preferably with varying rates of ball delivery and varying angular excursions between the forehand and the backhand throw. Additional features might include a variable height in the throws, such as by way of a mechanical adjustment of the device, or more preferably by way of a readily controllable or even a random variation in the height of the pitches, varying between controllable limits. In some instances a remote control is preferred in order to provide maximum diversity in the throws without requiring frequency adjustments at the machine itself. It is therefore these various desired characteristics and objectives to which the present invention is directed.